Australia has had wetter weather over the past 50 years despite many parts of the country currently battling drought conditions, according to climate scientists.

A study of 100 years of rainfall data shows Australia's overall average rainfall has increased about 10% each decade since 1952, says CSIRO atmospheric climate researcher, Dr Ian Smith.

Smith, who presented his findings at the Australia New Zealand Climate and Water Forum in Victoria this week, said the steady increase over such a long period was unusual and significant as it ruled out expected year-to-year rainfall fluctuations.

"The wetter conditions have occurred in the more sparsely populated regions in western, northern and central parts of Australia during the summer-half of the year," said Smith, who also published his study in a recent issue of the Australian Meteorological Magazine.

But southern and southwest parts of the country have had drier winter-half weather since the 1970s, and the south-east since 1996.

The results may also signal climate change scientists suggested more than 20 years ago, he said.

"They didn't have access to the computer models and made their suggestions based on observations," said Smith.

"The fact that we are seeing these things now is important as we can get a better handle on the path the climate will take."

In a related study published recently in the journal Geophysical Research Letters, Smith and his colleague Dr Richard Wardle from the University of Melbourne found Australia's increased overall average summer rainfall coincided with higher continental and Indian Ocean temperatures.

Using computer climate modelling they learned higher land temperatures caused the monsoon region to become wetter and cooler in summer while drier southern regions become wetter and warmer.

"This result is important because it indicates that a regional response to climate change is not necessarily the same as the overall large-scale response," said Smith.